Most large solar arrays use flat panels or curved mirrors to capture sunlight.

Cool Earth Solar's arrays use big, inflatable plastic tubes.

The Livermore startup, founded in 2007, claims its inflatable gear can generate as much electricity as standard solar systems while using half as much material. That approach could radically cut costs.

But first, Cool Earth must prove that its systems can perform as advertised in the field. So on Wednesday, the company announced a partnership with Sandia National Laboratories to test Cool Earth's technology over the next five years at Sandia's Livermore campus.

"They've got a long and rich history with solar," said Rob Lamkin, the company's chief executive officer. "It's a third-party evaluation that people respect."

Born during the Cold War, the national labs operate under a constant blanket of security that makes impromptu visits by business executives and researchers difficult. The Open Campus should improve access for companies that want to tap the labs' deep research into fields such as fuel combustion and cybersecurity.

"We're in a very different world from when the labs were founded," said Andy McIlroy, Sandia's senior manager for Open Campus development efforts. "For us to deliver on our mission, we have to be engaged nationally and globally in ways we haven't done in the past. We need to bring our capabilities to the outside world and bring the outside world into our labs as well."

Cool Earth, whose office lies about 2 miles from the labs, has raised over $21 million in venture funding to date.

The company's technology uses one of the cheapest materials around - thin plastic film - to focus sunlight. Each inflatable tube - about 36 inches in diameter and 24 feet long - contains solar cells running the length of its interior, either in a continuous strip or spaced 6 inches apart.

The plastic is manufactured in a way that enhances its refractive properties, Lamkin said. Once inflated, the curved plastic focuses light on the solar strips.

The tubes weigh less than 5 pounds, so mounting is easy. They're also aerodynamic, so they don't blow around in the wind, Lamkin said. They're designed to be deployed in large clusters, not on residential rooftops.

Of course, the standard, flat solar panel cost about $8 per watt when Cool Earth was founded, by Lamkin's estimate. Now the typical manufacturing cost is below $1. But Lamkin says Cool Earth's technology may be able to undercut that price.

"We think there's room to make solar cheaper yet," he said. "We're either going to prove ourselves right or wrong, and this deployment is going to do it."